Scientists from the School of Freshwater Sciences at the University of Wisconsin-Milwaukee were examining water samples for PPCPs, chemicals that have been derived from pharmaceuticals and personal care products. The effects of these pollutants have been studied in rivers, harbors and other watersheds. But no previous studies ever assessed PPCPs offshore in Lake Michigan -- the world's sixth-largest lake by volume. It was thought human, industrial and agricultural wastewater contaminants would be diluted by the sheer amount of water that Lake Michigan holds.

"There's a belief with very large bodies of water that the solution to pollution is dilution," Rebecca Klaper, one of the co-authors of the study at the School of Freshwater Sciences, told The Huffington Post.